JERUSALEM - High up in an empty, mountainous expanse east of this city there is a stone patio with a plaque marking the cornerstone of a future Jewish community. Dedicated in 2009, the plaque promises the new city will be built "adjacent to the united Jerusalem, which will be quickly re-established."

Jerusalem, which both Israel and the Palestinians see as their capital, is anything but united, with fights over its development posing perhaps the greatest threat to the prospects of peace. And beyond the cornerstone, nothing has been erected since in this contentious 4.6-square-mile area, known as E1, where there are more goats than people.

But Israel's announcement Friday that it was moving ahead with zoning and planning preparations for the area could change all that, and many fear it could close the window on the chance for a two-state solution to the Israeli-Palestinian conflict.

Construction in E1, in West Bank territory that Israel captured in the 1967 war, would connect the large Jewish settlement of Ma'ale Adumim to Jerusalem, dividing the West Bank in two. The Palestinian cities of Ramallah and Bethlehem would be cut off from the capital, making the contiguous Palestinian state endorsed by the United Nations last week virtually impossible.

Although Israeli officials did not call the move retaliation for the U.N. vote, most people here assumed the timing was not coincidental. "It's like two 3-year-old children playing, and one is hitting and the other is slapping instead of sitting down," said Alex Lash, 56, an Israeli. "It's a never-ending story: We are doing something, they are doing something, one movement brings the other side's movement. There is no end for that."

Zakaria al-Qaq, a professor of national security at Al Quds University and a resident of the East Jerusalem neighborhood of Silwan, also described the situation as a hopeless "cycle of action and reaction," and said that Prime Minister Benjamin Netanyahu was under pressure to act because of the Israeli elections on Jan. 22.

"Maybe the Palestinians got something on paper and morally, but he got something on the ground," Al-Qaq said. "Netanyahu is trying to enforce something on the ground and gain the hearts and minds of the Israeli public. It's a strong message to the Palestinian leadership that Netanyahu is not without cards in his hand."

The development of E1, a project the United States has blocked several times since 1994, has long been seen as a diplomatic third rail, and several experts said that they expected that Israel may once again back down from building there. But several other controversial housing projects within Jerusalem have sped forward in recent months, raising the ire of the Palestinian leadership, left-leaning Israelis and the international community, most of whom see the settlements as a violation of international law.

Along with zoning and planning for E1, Israel on Thursday approved 3,000 new housing units in unspecified parts of East Jerusalem and the West Bank. Dani Seidemann, a Jerusalem lawyer and longtime anti-settlement activist, said that even before the latest decision, the government had issued tenders for the construction of 2,366 units in 2012, more than twice the number built in the previous three years combined.

Israel began building and expanding East Jerusalem in 1968, shortly after it wrested control of the area from Jordan.